(Adds details of bill, politics and background in paragraphs 5-6 and 11-13; byline)

By David Schwartz

PHOENIX, April 15 (Reuters) - Arizona Governor Jan Brewer on Tuesday signed into a law a bill allowing state health authorities to conduct surprise inspections of abortion clinics without first obtaining a warrant, handing another victory to abortion foes.

The Republican-backed bill, which gained final legislative approval from the state Senate last week, removes a provision from state law requiring a judge to sign off on any spot inspections conducted at the nine clinics in Arizona licensed to perform abortions.

No other medical facilities in the state require such a warrant for unannounced inspections.

"This legislation will ensure that the Arizona Department of Health Services has the authority to appropriately protect the health and safety of all patients," gubernatorial spokesman Andrew Wilder said in announcing that Brewer, a Republican, had signed the measure.

The governor herself made no comment.

Supporters of the bill argued that abortion clinics should be subject to the same level of oversight as other medical facilities and that requiring court-approved warrants for unannounced inspections could delay such scrutiny.

Critics of the measure called it an unnecessary government intrusion that had little to do with public safety.

Instead, they cast the measure as open to abuse by officials with an anti-abortion agenda who might use increased latitude for inspections to interfere with clinic operations, effectively restraining legal access to abortion in the state.

Arizona now joins 10 other states that allow for warrantless surprise inspections of abortion clinics, according to the Guttmacher Institute, a nonprofit sexual health organization.

Abortion-rights advocates have said they would challenge the measure in court if it became law, which adds to a string of abortion controls on the books in Arizona that rank among the most restrictive in the nation.

In 2012, Arizona enacted a law banning most abortions after 20 weeks of pregnancy, though a federal appeals court struck down that statute last year.

Arizona lawmakers previously approved warrantless surprise inspections for abortion clinics in 1999, but a federal appeals court struck down that measure as unconstitutional.

Abortion foes argue that warrantless inspections can now pass court muster under a new set of abortion clinic regulations adopted by Arizona in 2010. Abortion rights advocates disagree. (Reporting by David Schwartz in Phoenix; Writing by Steve Gorman in Los Angeles; Editing by Dan Whitcomb, Eric Walsh and Mohammad Zargham)